Thanks Lasse, I was thinking of this one where he (J.W.) does a pulser from
a mercury reed relay near the end... maybe the diode turn on/ off time app note.
here,
http://cds.linear.com/docs/en/application-note/an122f.pdf
AN94 (taming of the slew) is nice too.
George h.
>
> -Lasse
>
>
>
>
>
> -Lasse
Reply by JW●May 13, 20142014-05-13
On Mon, 12 May 2014 15:10:07 -0400 Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote in Message id:
<55mdnb33iLUSgezOnZ2dnUVZ_sednZ2d@supernews.com>:
>It's my favourite general-purpose high speed scope. I have a couple of
>500-MHz ones, which are about the fastest that still have the 1 Mohm
>input option, but for anything I can use 50-ohms for, or can hang a FET
>probe on, the 694C is the proverbial bee's knees. 125 ps rise time, no
>overshoot, whee!
>
>Mine has the 2Msample memory as well, which is a win, and a nice bright
>display.
2M was not available in the TDS600 series. The maximum memory was 120K per
channel for the TDS694C (option 1M) The TDS694X was the only one that had
any memory options.
What's interesting is that the TDS684C acquisition board is laid out for
larger memory chips - I've always wondered what would happen if I were to
populate them...
Reply by whit3rd●May 12, 20142014-05-12
On Monday, May 12, 2014 3:39:03 AM UTC-7, haitic...@gmail.com wrote:
> I have a Tek TDS694C I will be selling, and I'd like to demo it's high speed
> performance by showing it detecting a rise time...
> Is there a chip which will show a fast rise time? I believe they use some kind of
> high speed fpga?
FPGA's are slugs. You'd do better with a discrete solution,
or even a mercury-wetted pulser (and with a length of good
coax cable, that makes a nice Blumlein pulse generator).
<http://en.wikipedia.org/wiki/Pulse_forming_network>
Reply by Lasse Langwadt Christensen●May 12, 20142014-05-12
Den mandag den 12. maj 2014 15.06.00 UTC+2 skrev George Herold:
> On Monday, May 12, 2014 6:39:03 AM UTC-4, haitic...@gmail.com wrote:
>
> > Greetings
>
> > I have a Tek TDS694C I will be selling, and I'd like to demo it's high speed
>
> > performance by showing it detecting a rise time - I'm trying to remember exactly
>
> > what that is - somewhere in picosecnd range?
>
> It's something like, 1/3 or 1/pi times 1/bandwidth, so 1GHz is 300ps of something.
>
>
>
> There's a nice J. Williams article about fast edges/ pulses
>
> AN47? (maybe?)
>
On 05/12/2014 12:07 PM, haiticare2011@gmail.com wrote:
> On Monday, May 12, 2014 10:35:54 AM UTC-4, Phil Hobbs wrote:
>> On 05/12/2014 10:33 AM, Bill Sloman wrote:
>>
>>> On Monday, 12 May 2014 20:39:03 UTC+10, haitic...@gmail.com wrote:
>>
>>>> Greetings
>>
>>>>
>>
>>>> I have a Tek TDS694C I will be selling, and I'd like to demo it's high speed performance by showing it detecting a rise time - I'm trying to remember exactly what that is - somewhere in picosecnd range?
>>
>>>>
>>
>>>> Is there a chip which will show a fast rise time? I believe they use some kind of high speed fpga?
>>
>>>
>>
>>> John Larkin is the expert here. When I had to do something similar - a long time ago - I used a well-specified step-recovery diode from HP.
>>
>>>
>>
>>> If you could find one in a low-inductance - which is to say, a small circuit mount - package, and mount it in a transmission line environment, above a good ground plane, you might have got down to a 100psec risetime.
>>
>>>
>>
>>> John seems to do better. Some ECLinPS parts are supposed to be in the same ball-park, and will drive 50R terminated transmission lines, as will a step recovery diode.
>>
>>>
>>
>>
>>
>> Well, the real answer of course is to hang onto the TDS694C, and get an
>>
>> 11801C and SD-24 TDR head to test it with. ;)
> hmmmm What is the tds64c god for, practically?
It's my favourite general-purpose high speed scope. I have a couple of
500-MHz ones, which are about the fastest that still have the 1 Mohm
input option, but for anything I can use 50-ohms for, or can hang a FET
probe on, the 694C is the proverbial bee's knees. 125 ps rise time, no
overshoot, whee!
Mine has the 2Msample memory as well, which is a win, and a nice bright
display.
Sampling scopes require many triggers per waveform (512 in the case of
the 11801 series), and can't look backwards in time before their
triggers. (That's why the 11802 comes with two coiled hardline delay
lines in the mainframe.)
Sampling scope triggering is also external-only, which takes a bit of
futzing around if you're not doing stimulus-response type measurements.
The 11801 will give you a factor of 8 faster response than that with the
ordinary plugins, and a factor of nearly 20 with the fastest ones.
That's fast enough that you have to put the sampling head right at the
circuit, which is where the extender cables come in.
Cheers
Phil "Scope junkie" Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics
160 North State Road #203
Briarcliff Manor NY 10510
hobbs at electrooptical dot net
http://electrooptical.net
Reply by Joerg●May 12, 20142014-05-12
haiticare2011@gmail.com wrote:
> Greetings
> I have a Tek TDS694C I will be selling, and I'd like to demo it's high speed
> performance by showing it detecting a rise time - I'm trying to remember exactly
> what that is - somewhere in picosecnd range?
>
> Is there a chip which will show a fast rise time? I believe they use some kind of
> high speed fpga?
>
I guess a fall time would also count. How high is "high speed"? A simple
BFR92 driven hard can give you fall times in the 100psec range. That
would be a part that could already be in a parts bin somewhere. The
BFS17 is good as well but it depends which kind you have.
--
Regards, Joerg
http://www.analogconsultants.com/
Reply by John Larkin●May 12, 20142014-05-12
On Mon, 12 May 2014 10:35:54 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:
>On 05/12/2014 10:33 AM, Bill Sloman wrote:
>> On Monday, 12 May 2014 20:39:03 UTC+10, haitic...@gmail.com wrote:
>>> Greetings
>>>
>>> I have a Tek TDS694C I will be selling, and I'd like to demo it's high speed performance by showing it detecting a rise time - I'm trying to remember exactly what that is - somewhere in picosecnd range?
>>>
>>> Is there a chip which will show a fast rise time? I believe they use some kind of high speed fpga?
>>
>> John Larkin is the expert here. When I had to do something similar - a long time ago - I used a well-specified step-recovery diode from HP.
>>
>> If you could find one in a low-inductance - which is to say, a small circuit mount - package, and mount it in a transmission line environment, above a good ground plane, you might have got down to a 100psec risetime.
>>
>> John seems to do better. Some ECLinPS parts are supposed to be in the same ball-park, and will drive 50R terminated transmission lines, as will a step recovery diode.
>>
>
>Well, the real answer of course is to hang onto the TDS694C, and get an
>11801C and SD-24 TDR head to test it with. ;)
>
>Cheers
>
>Phil Hobbs
Yeah, the TDR step (and the calibrator output) are metrology-class rising edges,
in the 30 ps range.
A lot of cmos chips will make pretty clean edges in the ballpark of 500 ps.
NL37WZ16US is great, 11 cents, but the US8 package is nasty.
DS90LV012ATMF is basically a r-r comparator with a 500 ps output. SOT23,
reasonable to solder down on some hacked copperclad.
The Onsemi Gigacomm parts can make really sweet edges down around 50 ps, but
need to be handled very carefully, definitely not x-acto knife stuff.
You can reasonably breadboard with EclipsLite and EclipsPlus parts
https://dl.dropboxusercontent.com/u/53724080/Protos/BB_fast.JPG
225 ps typ rise/fall for that EL07.
--
John Larkin Highland Technology Inc
www.highlandtechnology.com jlarkin at highlandtechnology dot com
Precision electronic instrumentation
Reply by ●May 12, 20142014-05-12
On Monday, May 12, 2014 10:35:54 AM UTC-4, Phil Hobbs wrote:
> On 05/12/2014 10:33 AM, Bill Sloman wrote:
>
> > On Monday, 12 May 2014 20:39:03 UTC+10, haitic...@gmail.com wrote:
>
> >> Greetings
>
> >>
>
> >> I have a Tek TDS694C I will be selling, and I'd like to demo it's high speed performance by showing it detecting a rise time - I'm trying to remember exactly what that is - somewhere in picosecnd range?
>
> >>
>
> >> Is there a chip which will show a fast rise time? I believe they use some kind of high speed fpga?
>
> >
>
> > John Larkin is the expert here. When I had to do something similar - a long time ago - I used a well-specified step-recovery diode from HP.
>
> >
>
> > If you could find one in a low-inductance - which is to say, a small circuit mount - package, and mount it in a transmission line environment, above a good ground plane, you might have got down to a 100psec risetime.
>
> >
>
> > John seems to do better. Some ECLinPS parts are supposed to be in the same ball-park, and will drive 50R terminated transmission lines, as will a step recovery diode.
>
> >
>
>
>
> Well, the real answer of course is to hang onto the TDS694C, and get an
>
> 11801C and SD-24 TDR head to test it with. ;)
>
>
>
> Cheers
>
>
>
> Phil Hobbs
>
>
>
> --
>
> Dr Philip C D Hobbs
>
> Principal Consultant
>
> ElectroOptical Innovations LLC
>
> Optics, Electro-optics, Photonics, Analog Electronics
>
>
>
> 160 North State Road #203
>
> Briarcliff Manor NY 10510
>
>
>
> hobbs at electrooptical dot net
>
> http://electrooptical.net
hmmmm What is the tds64c god for, practically?
jb
Reply by Phil Hobbs●May 12, 20142014-05-12
On 05/12/2014 10:33 AM, Bill Sloman wrote:
> On Monday, 12 May 2014 20:39:03 UTC+10, haitic...@gmail.com wrote:
>> Greetings
>>
>> I have a Tek TDS694C I will be selling, and I'd like to demo it's high speed performance by showing it detecting a rise time - I'm trying to remember exactly what that is - somewhere in picosecnd range?
>>
>> Is there a chip which will show a fast rise time? I believe they use some kind of high speed fpga?
>
> John Larkin is the expert here. When I had to do something similar - a long time ago - I used a well-specified step-recovery diode from HP.
>
> If you could find one in a low-inductance - which is to say, a small circuit mount - package, and mount it in a transmission line environment, above a good ground plane, you might have got down to a 100psec risetime.
>
> John seems to do better. Some ECLinPS parts are supposed to be in the same ball-park, and will drive 50R terminated transmission lines, as will a step recovery diode.
>
Well, the real answer of course is to hang onto the TDS694C, and get an
11801C and SD-24 TDR head to test it with. ;)
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics
160 North State Road #203
Briarcliff Manor NY 10510
hobbs at electrooptical dot net
http://electrooptical.net
Reply by Bill Sloman●May 12, 20142014-05-12
On Monday, 12 May 2014 20:39:03 UTC+10, haitic...@gmail.com wrote:
> Greetings
>
> I have a Tek TDS694C I will be selling, and I'd like to demo it's high speed performance by showing it detecting a rise time - I'm trying to remember exactly what that is - somewhere in picosecnd range?
>
> Is there a chip which will show a fast rise time? I believe they use some kind of high speed fpga?
John Larkin is the expert here. When I had to do something similar - a long time ago - I used a well-specified step-recovery diode from HP.
If you could find one in a low-inductance - which is to say, a small circuit mount - package, and mount it in a transmission line environment, above a good ground plane, you might have got down to a 100psec risetime.
John seems to do better. Some ECLinPS parts are supposed to be in the same ball-park, and will drive 50R terminated transmission lines, as will a step recovery diode.
--
Bill Sloman, Sydney